261988608 has 72 divisors (see below), whose sum is σ = 796898368. Its totient is φ = 74852352.

The previous prime is 261988591. The next prime is 261988609. The reversal of 261988608 is 806889162.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (261988609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18991 + ... + 29742.

Almost surely, 2^261988608 is an apocalyptic number.

261988608 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

261988608 is an abundant number, since it is smaller than the sum of its proper divisors (534909760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261988608 is an equidigital number, since it uses as much as digits as its factorization.

261988608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48759 (or 48745 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 48.

The square root of 261988608 is about 16186.0621523581. The cubic root of 261988608 is about 639.8735166714.

The spelling of 261988608 in words is "two hundred sixty-one million, nine hundred eighty-eight thousand, six hundred eight".